There’s some old slang in the computer biz, calling something Big Iron. Basically that meant mainframes, back in the day when workstations were taking over. Not so much any more. I imagine the phrase could be used for other things these days – a 1957 Cadillac or an anvil.
Anyway, this is Big Iron of the sewing notions persuasion. It’s a grommet setter for #12 drapery grommets. The kind of big grommet you put the rod through.
Those are the grommets, to the right. That small plastic thing is a a template for placing the holes.
I had to measure, mark, then re-measure and re-mark to ge the spacing even. Then finally cut the holes before I could thwack the grommets in. It was a bit scary, cutting such large holes in the drapery header, but…